As can be seen by reference to the following U.S. Pat. No's. 3,042,215; 4,266,452; 4,151,823 and 3,912,633, there has been quite a bit of inventive activity related to oil filter, per se, filter wrenches, and means to facilitate the changing of the oil filter.
Most of the oil filters in use today are the spin-on variety; wherein the filter body is provided with a centrally disposed female threaded portion, which cooperates with a complementary male threaded portion on the engine mounting plate, in a well recognized manner.
The installation and removal of the oil filter is intended to be a relatively simple operation which is accomplished by rotating the filter body in a clockwise direction to engage the threaded portions in the installation phase; and by rotating the filter body in the counter-clockwise direction to disengage the threaded portions in the removal phase.
In theory, this procedure is simple and foolproof; however, the automotive industry designers have complicated matters by invariably installing the oil filters in virtually inaccessible areas, or locations having very close tolerances. This is particularly true in the case of most of the front wheel drive vehicles manufactured both here and abroad. In addition, the use of currently available filter wrenches, under these circumstances, is usually met with very poor performance, and many times results in damaged filters.
As a result of this problem the present improved oil filter construction was developed to save time in both phases of filter changing, and to allow auto designers greater freedom in the placement and design of engines. However, the greatest benefit will be to the auto owners, who change their own filters at home, and who have struggled for years with skinned knuckles and frustrations.